Case 9 Anatomy Flashcards
what is the level of the hyoid bone?
C3
what is the level of the lower border of the cricoid cartilage?
C6
what is the level of the thyroid notch?
C4
what is the level of the suprasternal notch?
T2/3
what is the thyroid gland made up of?
an isthmus and two lateral lobes
- in some cases, a pyramidal lobe is also present
where does apex and base of lateral lobe extend to?
- apex extends up to the oblique lines of the thyroid cartilage
- base to the level of the fourth or fifth tracheal ring
which tracheal rings does the isthmus cross anterior to?
2nd, 3rd and 4th
where does the pyramidal lobe project upwards from and where to?
from the isthmus to the left of the midline
what is the thyroid gland enclosed by?
a thin connective tissue capsule, from which septa project into the gland
what surrounds the glad and the capsule (thin connective tissue)?
a loose connective tissue sheath
what is this sheath derived from?
the pretracheal fascia (one of layers of cervical fascia)
what are the anterolateral relations of the thyroid gland?
- Anterior border of sternocleidomastoid
- Sternohyoid muscle
- Superior belly of omohyoid
- Sternothyroid muscle
what are the posterolateral relations of the thyroid gland?
- Vagus nerve
- Common carotid artery
- Carotid sheath
- Internal jugular vein
what are the medial relations of the thyroid gland?
- Cricothyroid muscle
- Recurrent laryngeal nerve
- Larynx
- Trachea
- Oesophagus
- External laryngeal nerve
- Pharynx
what are the anterior relations of the isthmus of the thyroid gland?
- Sternothyroid muscle
- Anterior jugular vein (blood vessel formed by the confluence of the superficial submandibular veins)
- Sternohyoid muscle
what are the posterior relations of the isthmus of the thyroid gland?
• Second, third and fourth rings of tracheal cartilages
where do the blood vessels supplying the thyroid gland lie?
between the capsule and the fascial sheath
what is the arterial supply of the thyroid gland?
- Arterial blood is supplied by the superior and inferior thyroid arteries; the superior thyroid artery supplies the upper pole of each lobe whilst the inferior thyroid artery supplies the posteroinferior aspect
- There is considerable anastomosis between vessels
where does the superior thyroid artery arise from?
the external carotid artery
which nerve runs alongside the superior thyroid artery?
external branch of superior laryngeal nerve??
where does the inferior thyroid artery arise from?
the thyrocervical trunk
where does the thyrocervical trunk arise from?
the subclavian artery
(branch of the subclavian artery arising from the first portion of the vessel – it’s located distally to the vertebral artery and proximally to the costocervical trunk)